/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package salve.eclipse.builder;

import java.io.InputStream;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.runtime.CoreException;

import salve.Bytecode;
import salve.BytecodeLoader;
import salve.util.StreamsUtil;

public class FileBytecodeLoader implements BytecodeLoader
{
    private final IFile file;

    public FileBytecodeLoader(IFile file)
    {
        if (file == null)
        {
            throw new IllegalArgumentException("Argument `file` cannot be null");
        }
        this.file = file;
    }

    public Bytecode loadBytecode(String className)
    {
        if (!file.getFullPath().toString().endsWith(className + ".class"))
        {
            return null;
        }
        try
        {
            InputStream in = file.getContents();
            final byte[] bytes = StreamsUtil.drain(in, "Could not read bytecode from {}", file
                    .getFullPath().toOSString());
            return new Bytecode(className, bytes, this);
        }
        catch (CoreException e)
        {
            throw new RuntimeException("Could not read contents of: " +
                    file.getFullPath().toOSString());
        }
    }
}
